Modern silviculture often requires the planting of large numbers of genetically identical plants that have been selected to have advantageous properties. Production of new plants by sexual reproduction, which yields botanic seeds, is usually not feasible. Asexual propagation, via the culturing of somatic or zygotic embryos, has been shown for some species to yield large numbers of genetically identical embryos, each having the capacity to develop into a normal plant. Plant embryos created by in vitro cultures, however, lack the natural protective and nutritive features of natural botanic seeds. Attempts have been made to provide the protective and nutritive structures found in natural botanic seeds to plant embryos cultured in a laboratory by using manufactured seeds. Manufactured seeds are described, for example, in U.S. Pat. Nos. 5,564,224; 5,687,504; 5,701,699; and 6,119,395. Problems with manufactured seeds remain. Both the rate of successful germination and the quality of germinants produced from manufactured seeds are lower than the rate and quality obtained from natural botanic seeds. Therefore, there is a need to improve the rate of germination and the quality of germinants obtained from manufactured seeds. The present invention addresses these and other needs.